The present invention relates to an engine protecting apparatus for a vehicle which stops an engine when an abnormality occurs in the engine.
Several kinds of vehicles are equipped with a sensor/meter for displaying the operating condition of the engine, for example, cooling water temperature, lubricating oil pressure and oil temperature. An operator of the vehicle determines whether the abnormality of the engine exists or not based on values displayed on the meters. If an abnormality exists, the vehicle operator must address the malfunction in order to prevent accidents.
However, when the operator is distracted to work hard, or when the operator is negligent in addressing the abnormality, the operator continues operating the vehicle without fixing the problem and possible engine change results. In order to prevent such a risk caused by the abnormality of the engine, a technique for stopping an engine automatically when the error occurs in the engine was proposed.
FIG. 3 shows a circuit diagram illustrating electrical components of a conventional engine protecting apparatus. A battery 50 is connected at its negative (minus) terminal to the ground (GND) and at its positive (plus) terminal to a key switch 51. An ignition terminal (IG) of the key switch 51 is connected to an ignition coil 53 disposed in an ignition circuit via a relay 52. A starter terminal (ST) of the key switch is connected to a starter motor (not shown). Each of a lubricating oil pressure switch 54 and a cooling water temperature switch 55 is connected in series to a warning lamp 56 and also connected to a relay 59 via diodes 57, 58. The relay 59 is connected to the relay 52 via a relay 61 which closes when a timer 60, which de-actuates the engine protecting apparatus, times up.
In the above conventional apparatus, when the abnormality of the engine occurs, and when at least one of the cooling water temperature switch 55 and the lubricating oil pressure switch 54 is actuated, the warning lamp 56 lights. Meanwhile, the relay 52 opens to stop the engine immediately. Upon starting the engine, the timer 60 and the relay 61 make the engine protecting apparatus in an unoperated condition until the lubricating oil pressure reaches its predetermined value.
However, when the conventional engine protecting apparatus mentioned above is installed in the vehicle having the power assist device, and when the engine stops due to abnormality of the engine, i.e. over heat, during the vehicle moving, the power assist device is de-actuated immediately. Therefore, braking and steering is deteriorated and moving the vehicle to a desired place for parking is difficult.
It is an aspect of the present invention to provide a vehicle including a power assist device with an engine protecting apparatus that makes it possible to steer and brake the vehicle, even after any abnormality of the engine is detected.
In order to attain the above aspect, the engine protecting apparatus for the vehicle includes a battery, a key switch, a condition switch, a timer and a timer-operative switch. The battery supplies an electric current to the ignition circuit of the engine. The key switch is disposed between the battery and the ignition circuit and has an ignition terminal. The condition switch turns on and off based on engine conditions. The condition switch is connected to the ignition terminal of the key switch. The timer is operatively connected to the ignition terminal of the key switch and has a predetermined period of time. The timer measures a time period from the condition switch turned on. The timer-operative switch is actuated by the timer. The timer-operative switch interrupts the electric current flowing to the ignition circuit when the timer measures the predetermined time period. Therefore, the engine continues to run for a while even after something abnormal is detected by the condition switch, so that the operator can move the vehicle to the safe parking place until the engine stops.